Their inclusion has added a vibrancy and unpredictability to the national side but Martinez stressed they should not bear the burden of unrealistic expectation.

"My message to every English fan and supporter in general is that we should embrace the younger generation - and it is phenomenal to have that - who have been called up by the England manager," the Spaniard added.

"But we have to understand we carry a responsibility of allowing the young players to have a positive experience, whatever that is.

"Then we can allow them to grow and put them in a position where they have (played) 300 to 400 games and can then be tested and pushed to see if they can win a World Cup.

"At the moment it is making sure they are protected in their environment, are allowed to enjoy their football and whatever they bring to the occasion is going to be a great learning curve for the future.

"Like any job in any line of work you are better by the experience you get and it is having the opportunity to make mistakes and grow and just become better out of that.

"Whatever they bring to this World Cup is a bonus. We should be looking further ahead to see the results of these youngsters.

"Experience in a World Cup has to be a positive one whatever the results are.

"But it is something we do quite often - we build the expectations and then lose the opportunity of fulfilling that potential and having a special player for the future.

"We are not the only ones, there are many nations who build expectations so quickly and then put them on young shoulders and that is unfair.

"There is not a written rule of what you should do. You should allow them to enjoy the experience, whatever it is, and then set the next target for them and continually evaluate them and give them an area to improve and focus on."

Reports Chelsea are to offer Romelu Lukaku a new contract could be good news for Everton, for whom he scored 16 goals in 33 appearances in a season-long loan.

Martinez is keen to take the Belgium international back to Goodison Park next season but knows a decent World Cup would push the striker's value beyond what the Toffees could afford should he become available to buy.

Chelsea appear keen to retain the 21-year-old for the foreseeable future so at the very least they can make a profit on the Â£17million they paid Anderlecht in 2011 and that may benefit Everton again next season.

Martinez is more hopeful of retaining Gareth Barry, who is out of contract with Manchester City after his loan spell at Goodison, but is relying on the midfielder opting to stay with a club where he was happy and guaranteed a starting place as the Spaniard knows they cannot compete with salaries offered elsewhere.

The Everton boss will continue to utilise the loan market - and tap into the club's youth system - next season as he looks to add two strikers, a right winger, defensive midfielder and a defender to his squad.

Striker Apostolos Vellios, who failed to play a first-team game this season, has left the club after his contract expired, however, talks over a new deal have opened with 33-year-old full-back Tony Hibbert who is also out of contract next month.